Main spars for aircraft, having a tapered shape to the lengthwise direction thereof, have been produced by cutting a shaped article having a uniform sectional shape with an expensive NC spar mirror, NC plano-mirror, NC profiler or the like by many working steps. As unworked billets or pipes for high-pressure fuel ducts for cars and others, metal pipes of miscellaneous shapes with uneven thickness, such as those shown in FIG. 3 and FIG. 4, have been employed. Heretofore, such pipes have been produced by shaping a pipe with uneven thickness by casting or extrusion of an unworked billet 9', as shown in FIG. 11 and FIG. 12, followed by cutting the thick portion 9" of it with a milling cutter or the like, as shown in FIG. 13 and FIG. 14.
However, the working process is uneconomical and unfavorable since it needs much time and much labor and additionally generates a large amount of shavings in the cutting step. In addition, since the metal flow m' of the product obtained is cut in the middle thereof due to the cutting operation, the product often has another problem that the strength thereof lowers.
The object of the present invention is to overcome the above-mentioned problems and to provide a long extruded metal article of miscellaneous shapes and a method of producing it, in which a long metal billet is extruded to give a sectional profile of miscellaneous shapes in the lengthwise direction of the extruded and shaped metal article so that the additional working of the shaped metal article for reducing the thick wall portion thereof by cutting or the like operation is minimized.